Mounting of sheet material

ABSTRACT

A pair of spaced apart gripping formations are located at an angle to each other, the gripping formations being operative to engage a pair of adjacent edges of a backing member meeting at a common corner in positions spaced from the common corner and also to engage sheet material superimposed on a front face of the backing member. A resilient locking element connects the two gripping formations and is arranged to extend along the rear of the backing member across the common corner in a position spaced therefrom, and a catch formation extends transversely from the locking element and is engageable and disengageable with a recess in the rear face of the backing member by displacement of the locking element in a direction transverse to the plane of the backing member, the locking element being operative resiliently to bias the catch formation towards engagement with the recess in the backing member.

United States Patent 1 Heilmeier 1 MOUNTING OF SHEET MATERIAL Horst Joseph Heilmeier, 107 Struben St., Benoni, South Africa 22 Filed: Nov. 21, 1972 21 App1.No.:308,505

[76] Inventor:

[30] Foreign Application Priority Data Dec. 9, 1971 South Africa 70/8178 [52] US. Cl. 248/490 [51] Int. Cl A47g l/16 [58] Field of Search 248/488, 490, 498; 52/621, 52/623; 24/73 SP, 73 SM; 40/1521; 269/41; 287/l89.36 H

FOREIGN PATENTS OR APPLICATIONS 635,806 4/1950 Great Britain 248/490 Primary Examiner-William H. Schultz Attorney, Agent, or Firm-Marshall & Yeasting 57] ABSTRACT A pair of spaced apart gripping formations are located at an angle to each other, the gripping formations being operative to engage a pair of adjacent edges of a backing member meeting at a common corner in positions spaced from the common corner and also to engage sheet material superimposed on a front face of the backing member. A resilient locking element connects the two gripping formations and is arranged to extend along the rear of the backing member across the common corner in a position spaced therefrom, and a catch formation extends transversely from the locking element and is engageable and disengageable with a recess in the rear face of the backing member by displacement of the locking element in a direction transverse to the plane of the backing member, the locking element being operative resiliently to bias the catch formation towards engagement with the recess in the backing member.

10 Claims, 4 Drawing Figures MOUNTING OF SHEET MATERIAL BACKGROUND OF THE INVENTION This invention relates to the mounting of sheet material, such as paintings, prints, posters, photographs, drawings, maps and the like.

It is well known that where paintings, prints, photographs, posters, drawings, maps and other material in sheet form are to be displayed or exhibited temporarily in art galleries, museums, exhibitions, shops, offices or the like, it is a problem to mount and demount the sheets without too much time, effort and expense being involved. Even when material in sheet form is to be mounted on a permanent or semi-permanent basis, the time and expense of achieving a suitable mounting can be a problem.

In order to meet the problem, it has been suggested to mount a sheet between a backing member of hardboard or the like and a glass or Perspex front cover by means of a plurality of metal clips adapted to press the backing member and the front cover together to trap the sheet between them. Such a known clip comprises a single channel-shaped portion adapted to receive one edge of the superimposed backing member, sheet and front cover assembly; and a resilient plate attached along one end thereof to the channel-shaped portion and bent to present along its opposite end a flange-like catch formation adapted to engage in a slot which is located in the rear face of the backing member and which extends substantially parallel to that edge of the backing member which is located in the channel-shaped portion of the clip.

The resilient plate presents a curved back which extends between and arches away from the channelshaped portion and the catch formation of the clip and from the backing member when viewed in cross-section on a line passing through the channel-shaped portion and the catch formation. By exerting pressure on the outwardly curved back of the resilient plate, the catch formation can be pressed into the slot in the rear face of the backing member, the slot being spaced from the edge of the backing member which is located in the channel-shaped portion a distance slightly larger than the normal spacing between the catch formation and the inner surface of the web of the channel-shaped portion, so that the plate has to be flattened against the action of its own resilience by pressure exerted on its outwardly curved back in order to displace the catch formation along the rear face of the backing member into the slot in the backing member. Once the catch formation has engaged the slot and the pressure on the curved back is released, the resilient plate tends to contract and draw the catch formation and the channelshaped portion towards each other, thereby to establish a grip by the channel-shaped portion on the superimposed backing member, sheet and front cover assembly.

For purposes of hanging the assembly, a hanging aperture is provided in the resilient plate of the clip in the region of the catch formation, the aperture being adapted to be engaged by a hook or like formation on a hanging cord, cable or the like.

In order to release the clip from the superimposed assembly, the catch formation is displaced longitudinally along the slot in which it engages until the catch formation twists out of the slot.

The resilient plate type of clip described above, is generally satisfactory in operation but it suffers from certain disadvantages. It is relatively expensive and since it engages over only one edge of the superimposed assembly, as many as eight clips are often required for each assembly, two clips being provided at each corner to engage a pair of adjacent edges meeting at that corner.

Also, problems are often encountered where the superimposed assembly is suspended from a single wall nail or hook by means of an inverted V-shaped hanging cord or cable engaged at opposite ends with the hanging apertures located at the catch formations of a pair of clips which are spaced apart along the upper edge of the superimposed assembly. It will be appreciated that the two arms of the inverted V formed by the hanging cord or cable, are located at acute angles to the upper edge of the superimposed assembly and to the slot or slots in which the catch formations of the clips engage. This causes forces having components acting longitudinally along the slot or slots, to be exerted on the clips at their catch formations. This tends to twist the catch formations out of the slot or slots, thereby to release them.

SUMMARY OF THE INVENTION It is an object of the present invention to provide new and improved clamping means for mounting sheet material on a backing member, with which the above disadvantages are avoided or at least minimised.

According to the invention clamping means suitable for mounting sheet material on a backing member comprises a pair of gripping formations located at an angle to each other and adapted to engage a pair of adjacent edges of a multi-lateral backing member meeting at a common corner and also to engage sheet material superimposed on a front face of the backing member; and a locking element connecting the two gripping formations and adapted to extend along the rear of the backing member across the common corner at which the pair of adjacent edges meet.

The clamping means may be so arranged that when the gripping formations are engaged with the pair of adjacent edges of the backing member, the locking element causes the gripping formations to be pulled into firm engagement with the adjacent edges of the backing member and sheet material superimposed on the front face of the backing member.

The gripping means may be adapted only to engage a superimposed assembly comprising the backing member and a sheet to be mounted on the backing member. Here the gripping formations may directly engage the backing member and the sheet to be mounted on the backing member. Alternatively, the gripping means may be adapted to engage a superimposed assembly comprising the backing member, a sheet to be mounted on the backing member and a sheet of transparent ma terial constituting a transparent front cover over the sheet to be mounted. Here the gripping formations may directly engage the backing member and the front cover only, the sheet to be mounted on the backing member being clamped between the backing member and the front cover.

In a preferred embodiment, the gripping formations are channel shaped. The width of the channels will be determined by the thickness of a superimposed assembly which is to be engaged by the channels.

The clamping means may be engaged with a pair of adjacent edges of a superimposed assembly by sliding the channel shaped gripping formations over such edges from the common corner at which they meet in the plane of the superimposed assembly.

The locking element may be shaped to pull the gripping formations into firm engagement with the adjacent edges of the backing member and sheet material superimposed on the front face of the backing member.

The locking element is preferably resilient.

The locking element may be provided with a catch formation engageable and disengageable with a recess in the rear face of the backing member by displacement of the locking element in a direction transverse to the plane of the backing member.

The catch formation may be in the nature of a projection extending transversely from the locking element.

In one embodiment of the invention, channel-shaped gripping formations extend in one direction from the locking element and intermediate the gripping formations a catch formation projects from the locking element in the same direction as the gripping formations.

The locking element may also present an attachment formation adapted to be engaged by means for hanging the backing member and one or more layers of sheets of material superimposed thereon.

The attachment formation may be associated with or may form part of the catch formation.

In one embodiment an attachment formation may comprise a bore of any suitable cross-sectional configuration passing at least partly through the locking element and adapted to receive the head of a hanging nail or the like. Preferably, the bore presents a step or shoulder adapted releasably to engage the head of the nail to inhibit withdrawal of the clamping means from the nail. The bore may also pass at least in part through the catch formation.

Additionally or alternatively to the nail receiving bore, an attachment formation may comprise a projection extending from the locking element in a direction opposite to the gripping formations in a position intermediate the gripping formations. Such an attachment projection may present a peripheral groove or like formation adapted to receive a hanging cord, cable or the like.

Where both an attachment projection and an attachment bore are provided, the bore may pass through the attachment projection.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view from one side of a clamping unit according to the invention.

FIG. 2 is a front view of the clamping unit of FIG. I seen from the opposite side.

FIG. 3 is a rear view of a rectangular backing member with four clamping units similar to that of FIGS. 1 and 2 engaged over the corners of the backing member.

FIG. 4 is a fragmentary sectional view on the line IV-IV in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT A clamping unit A comprises a pair of gripping formations 1 which are in the form of channels which are disposed at right angles to each other and which are adapted to engage over the edges of a pair of adjacent sides of a rectangular backing member 2 which meet at a common corner. A resilient locking element 3 is integrally connected at opposite ends with one-flange of each of the two gripping formations 1 so that the gripping formations extend in the same direction away from locking element 3. As can be seen from FIG. 1, locking element 3 does not lie in the same plane throughout its length, but has a shallow V-shaped configuration with the apex of the V pointing in the direction in which gripping formations 1 extend from locking element 3.

Channel shaped gripping formations I are adapted to receive a superimposed assembly comprising at least the backing member 2 and a sheet 4 which is to be mounted on the backing member 2. If required, the superimposed assembly may also include a transparent front cover 5, such as a sheet of glass or Perspex, which is located over the sheet 4.

Clamping unit A may be engaged with a pair of adjacent edges of the superimposed assembly by sliding the channel-shaped gripping formation 1 over such edges from the common corner at which they meet in the plane of the superimposed assembly. It may be necessary to pull the locking element 3 transversely away from the backing member so that the V-shaped locking element 3 tends to straighten, in order to move clamping unit A into its operative position shown in FIGS. 3 and 4.

Circular catch formation 6 projects from locking element 3 in the same direction as the two gripping formations 1 and in a position midway between the two gripping formations. As can be seen clearly from FIG. 4, catch formation 6 is adapted to engage in a complementary recess 10 in the rear face of the backing member 2 when the clamping unit A is in the operative position shown in FIG. 3.

The resilience and configuration of locking element 3 and the configuration of the clamping unit A as a whole are such that catch formation 6 is urged into its recess 10 and gripping formations 1 firmly press the superimposed assembly together.

It will be appreciated that when catch formation 6 is engaged with the recess 10 the clamping unit A cannot slide out of its operative position in a direction lying in the plane of the backing member 2. In order to disengage the clamping unit A, it is necessary to displace locking element 3 transversely away from backing member 2 so that catch formation 6 is lifted out of the recess 10 in the backing member 2.

The clamping unit A further includes attachment formation 7 which is disposed co-axially relative to catch formation 6 but projects from the locking element 3 in a direction opposite to that in which catch formation 6 projects. As can be seen clearly from FIG. 4, attachment formation 7 is provided with a peripheral groove in which a hanging cord, cable or the like (not shown) can be engaged.

A stepped bore 8 of rectangular cross-sectional configuration passes through catch formation 6 and attachment formation 7. Bore 8 is adapted to receive the head of a hanging nail 9 with the head of the nail engaging the step 8a to inhibit withdrawal of the clamping unit from the nail.

It will be apreciated that many variations in detail are possible without departing from the spirit of the invention. Clamping unit A may be made from any suitable material but is preferably integrally moulded from polymer material, such as polycarbonate. The width of channel shaped gripping formations 1 may be selected to suit the thickness of the superimposed assembly to be engaged by the gripping formations.

Any suitable backing member 2 may be used. Thus a backing member comprising a sheet hardboard or the like may be used.

I claim:

1. Clamping means suitable for mounting sheet material on a backing member, comprising a pair of spaced apart gripping formations located at an angle to each other, the gripping formations being operative to engage a pair of adjacent edges of the backing member meeting at a common corner in positions spaced from the common corner and also to engage sheet material superimposed on a front face of the backing member; a resilient locking element connecting the two gripping formations and arranged to extend along the rear of the backing member across the common corner in a position spaced therefrom; and a catch formation extending transversely from the locking element and being engageable and disengageable with a recess in the rear face of the backing member by displacement of the locking element in a direction transverse to the plane of the backing member, the locking element being operative resiliently to bias the catch formation towards engagement with the recess in the backing member.

2. Clamping means as claimed in claim 1, wherein the gripping formations are channel shaped.

3. Clamping means as claimed in claim 2, wherein the channel-shaped gripping formations extend in one direction from the locking element and the catch formation projects in the same direction as the gripping formations from the locking element in a position intermediate the gripping formations.

4. Clamping means as claimed in claim 1, wherein the locking element is shaped to pull the gripping formations into firm engagement with the adjacent edges of the backing member and sheet material superimposed on the front face of the backing member.

5. Clamping means as claimed in claim 1, wherein the locking element presents at least one attachment formation engageable by means for hanging the backing member.

6. Clamping means as claimed in claim 5, wherein the attachment formation comprises a projection extending from the locking element in a direction opposite to the gripping formations in a position intermediate the gripping formations.

7. Clamping means as claimed in claim 6, wherein the attachment projection presents a peripheral groove or like formation operative to receive a hanging cord, cable or the like.

8. Clamping means as claimed in claim 5, wherein the attachment formation comprises a transversely disposed stepped bore in the locking element, the stepped bore comprising a first portion located towards the side of the locking element opposite to that facing the backing member and having a cross-sectional dimension sufficient to pass the head of a headed hanging element, and a second portion of larger cross-sectional dimension communicating with the first portion and located towards the side of the locking element facing the backing member, the stepped bore presenting at the junction of the first and second portions thereof, a shoulder facing the backing member and operative releasably to'engage the head of the hanging element to inhibit withdrawal of the clamping means from the hanging element.

9. A clamping unit suitable for mounting sheet material on a backing member, comprising a pair of spaced apart channel-shaped gripping formations located at an angle to each other, the gripping formations being operative to engage a pair of adjacent edges of the backing member meeting at a common corner in positions spaced from the common corner and also to engage sheet material superimposed on a front face of the backing member; a resilient locking element connecting the two gripping formations and arranged to extend along the rear of the backing member across the common corner in a position spaced therefrom, the locking element having a shallow V-shaped configuration with the apex of the V pointing in the direction of the gripping formations; a catch formation projecting transversely from the locking element in a position intermediate the gripping formations, the catch formation being engageable and disengageable with a recess in the rear face of the backing member by displacement of the locking element in a direction transverse to the plane of the backing member; the locking element being operative resiliently to bias the catch formation towards engagement with the recess in the backing member; and at least one attachment formation presented by the locking element and engageable by means for hanging the backing member.

10. A mounted assembly comprising a backing member; at least one sheet of material superimposed on the backing member; and at least one clamping unit comprising a pair of spaced apart gripping formations located at an angle to each other, the gripping formations being operative to engage a pair of adjacent edges of the backing member meeting at a common corner in positions spaced from the common corner and also to engage sheet material superimposed on a front face of the backing member; a resilient locking element connecting the two gripping formations and arranged to extend along the rear of the backing member across the common corner in a position spaced therefrom; and a catch formation extending transversely from the locking element and being engageable and disengageable with a recess in the rear face of the backing member by displacement of the locking element in a direction transverse to the plane of the backing member, the locking element being operative resiliently to bias the catch formation towards engagement with the recess in the backing member. 

1. Clamping means suitable for mounting sheet material on a backing member, comprising a pair of spaced apart gripping formations located at an angle to each other, the gripping formations being operative to engage a pair of adjacent edges of the backing member meeting at a common corner in positions spaced from the common corner and also to engage sheet material superimposed on a front face of the backing member; a resilient locking element connecting the two gripping formations and arranged to extend along the rear of the backing member across the common corner in a position spaced therefrom; and a catch formation extending transversely from the locking element and being engageable and disengageable with a recess in the rear face of the backing member by displacement of the locking element in a direction transverse to the plane of the backing member, the locking element being operative resiliently to bias the catch formation towards engagement with the recess in the backing member.
 2. Clamping means as claimed in claim 1, wherein the gripping formations are channel shaped.
 3. Clamping means as claimed in claim 2, wherein the channel-shaped gripping formaTions extend in one direction from the locking element and the catch formation projects in the same direction as the gripping formations from the locking element in a position intermediate the gripping formations.
 4. Clamping means as claimed in claim 1, wherein the locking element is shaped to pull the gripping formations into firm engagement with the adjacent edges of the backing member and sheet material superimposed on the front face of the backing member.
 5. Clamping means as claimed in claim 1, wherein the locking element presents at least one attachment formation engageable by means for hanging the backing member.
 6. Clamping means as claimed in claim 5, wherein the attachment formation comprises a projection extending from the locking element in a direction opposite to the gripping formations in a position intermediate the gripping formations.
 7. Clamping means as claimed in claim 6, wherein the attachment projection presents a peripheral groove or like formation operative to receive a hanging cord, cable or the like.
 8. Clamping means as claimed in claim 5, wherein the attachment formation comprises a transversely disposed stepped bore in the locking element, the stepped bore comprising a first portion located towards the side of the locking element opposite to that facing the backing member and having a cross-sectional dimension sufficient to pass the head of a headed hanging element, and a second portion of larger cross-sectional dimension communicating with the first portion and located towards the side of the locking element facing the backing member, the stepped bore presenting at the junction of the first and second portions thereof, a shoulder facing the backing member and operative releasably to engage the head of the hanging element to inhibit withdrawal of the clamping means from the hanging element.
 9. A clamping unit suitable for mounting sheet material on a backing member, comprising a pair of spaced apart channel-shaped gripping formations located at an angle to each other, the gripping formations being operative to engage a pair of adjacent edges of the backing member meeting at a common corner in positions spaced from the common corner and also to engage sheet material superimposed on a front face of the backing member; a resilient locking element connecting the two gripping formations and arranged to extend along the rear of the backing member across the common corner in a position spaced therefrom, the locking element having a shallow V-shaped configuration with the apex of the V pointing in the direction of the gripping formations; a catch formation projecting transversely from the locking element in a position intermediate the gripping formations, the catch formation being engageable and disengageable with a recess in the rear face of the backing member by displacement of the locking element in a direction transverse to the plane of the backing member; the locking element being operative resiliently to bias the catch formation towards engagement with the recess in the backing member; and at least one attachment formation presented by the locking element and engageable by means for hanging the backing member.
 10. A mounted assembly comprising a backing member; at least one sheet of material superimposed on the backing member; and at least one clamping unit comprising a pair of spaced apart gripping formations located at an angle to each other, the gripping formations being operative to engage a pair of adjacent edges of the backing member meeting at a common corner in positions spaced from the common corner and also to engage sheet material superimposed on a front face of the backing member; a resilient locking element connecting the two gripping formations and arranged to extend along the rear of the backing member across the common corner in a position spaced therefrom; and a catch formation extending transversely from the locking element and being engageable and disengageable with a recess in the rear face of the backing member by displacement of the locking element in a direction transverse to the plane of the backing member, the locking element being operative resiliently to bias the catch formation towards engagement with the recess in the backing member. 